A hard disk may be provided with a cache for the hard disk, typically found in random access memory (RAM), to cache data that has been read from the hard disk. However, because the hard disk cache is located in the RAM, data which is to be written to the hard disk is unable to be cached in the cache of the hard disk, because if the computer system were to fail the data to be written to the hard disk would be lost due to the loss of power to the RAM.
In addition, for mobile computers, repeatedly accessing the hard disk is a power consuming activity that involves a power management policy that attempts to reduce the frequency of spinning up the hard disk and the continued use of the hard disk.